code: def test_whitening_init():
      whit = Whitening()
      assert whit.metric == "euclid"
      assert whit.dim_red is None
      assert not whit.verbose
  
file_path: pyRiemann/tests/test_preprocessing.py
imports: import numpy
  from numpy.testing import assert_array_almost_equal
  import pytest
  from pyriemann.spatialfilters import Whitening
  from pyriemann.utils.mean import mean_covariance
label_desc: Use image node_id 1 for calling a global function with example usage: test_whitening_init() without return types